Although many surgeons associate obesity with adverse outcomes, recent large, well-designed studies have been unable to show that obesity (defined as Body Mass Index (BMI) >30) is an independent risk factor for major morbidity or mortality after general abdominal surgery. Recently abdominal obesity (waist measurement >102cm in men and >88cm in women) has been shown to have better correlation with cardiovascular disease than BMI and is strongly associated with a clustering of risk factors for cardiovascular disease and diabetes (insulin resistance, hyperglycaemia, hypertension, dyslipidaemia and abdominal obesity) known as the metabolic syndrome. Waist circumference and waist/hip ratio are measures of abdominal obesity that correlate with the amount of intra-abdominal rather than subcutaneous or general body fat and may be a better measure of the risk of intra-operative complications and post-operative morbidity following abdominal surgery than BMI.